To meet user needs for multiple functions and compactness, the compound electric connector that meets a plurality of signal transmission protocols have become a trend in the development of electric connectors. In particular, signal transmission protocols are constantly updated. During the transitional period between new and old transmission protocols or between multiple and different signal transmission protocols, compound electric connectors that simultaneously comply with multiple transmission protocols are more convenient to use.
Currently, common signal transmission protocols are USB 2.0, USB 3.0 (USB is an abbreviation for Universal Serial Bus) and ESATA (which is an abbreviation of External Serial Advanced Technology Attachment). Therefore, compound electric receptacle connectors that are available for separately plugging in USB 2.0, USB 3.0 and ESATA receptacle connectors have been developed. For example, some have been disclosed by Taiwan New Patent Public Bulletin Number M357748 (corresponding Chinese patent application number 200810173163.4; corresponding United States Patent Publication Number US 2009111330A1). A preferred embodiment disclosed by patent number M357748 is an assembled structure that uses a detached tongue and comprises three types of terminals, wherein the first type of terminals are ESATA connector terminals. The second type of terminals are standard USB 2.0 connector terminals. The third type of terminals combine with the second type of terminals to jointly form USB 3.0 connector terminals. The third type of terminals and the tongue are integrally formed and disposed in the tongue and are roughly located in the middle of the tongue. The first type of terminals is installed on the upper surface of the tongue. The second type of terminals is installed on the lower surface of the tongue.
However, its tongue is a flat and straight plate body. The tongue is only connected to and fastened onto the insulating body through a fastening structure. The stability of the assembled combination is a concern and the tongue itself is structurally rather weak because it is rather thin. To install the second type of terminals, a terminal path is formed on the tongue that runs through the rear end of the tongue, thus leaving the strength of the tongue even more insufficient and making it harder to withstand the high plug in force or torque or an abnormal plug in state, and easily causing conditions the as a loose and broken tongue, etc.